docs: def _postpone_selected(self, p_pattern, p_mode):
          """
          Postpones selected todo item by <COUNT><PERIOD>.
  
          Returns True after 'postpone' command is called (i.e. p_pattern is valid
          <PERIOD>), False when p_pattern is invalid and None if p_pattern is
          digit (i.e. part of <COUNT>).
  
          p_pattern accepts digit (<COUNT>) or one of the <PERIOD> letters:
          'd'(ay), 'w'(eek), 'm'(onth), 'y'(ear). If digit is specified, it is
          appended to _pp_offset attribute. If p_pattern contains one of the
          <PERIOD> letters, 'postpone' command is forwarded to execution with
          value of _pp_offset attribute used as <COUNT>. If _pp_offset is None,
          <COUNT> is set to 1.
  
          p_mode should be one of 'postpone_s' or 'postpone'. It decides whether
          'postpone' command should be called with or without '-s' flag.
          """
          if p_pattern.isdigit():
              if not self._pp_offset:
                  self._pp_offset = ''
              self._pp_offset += p_pattern
              result = None
          else:
              if p_pattern in ['d', 'w', 'm', 'y', 'b']:
                  offset = self._pp_offset or '1'
                  if p_mode == 'postpone':
                      pp_cmd = 'cmd postpone {} '
                  else:
                      pp_cmd = 'cmd postpone -s {} '
                  pp_cmd += offset + p_pattern
                  self.resolve_action(pp_cmd)
                  result = True
              self._pp_offset = None
              result = False
          return result